Motor safety fuse



May 3l, 1938.

E. D. STASSEN MOTOR SAFETY FUSE Filed Sept. 14, 1936 @M 0 l2 o INVENTORATTORNEYS Patented May 31, 1938 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to motor safety fuses and has for an object toprovide a fuse that will be interposed in the ignition circuit and whichwill be mounted so that a combustible extremity will be mounted on theengine head and in the event of excessive heat the fuse will be meltedand the ignition circuit thus opened to prevent damage to the motor.

With the above and other objects in view the invention consists ofcertain novel details of construction and combinations of partshereinafter fully described and claimed, it being understood thatvarious modifications may be resorted to within the scope of theappended claim without departing from the spirit or sacrificing any ofthe advantages of the invention.

In the accompanying drawing forming part of this specification,

Figure 1 is a plan view of a motor equipped with a safety fuseconstructed in accordance with the invention.

Figure 2 is a side elevation of the fuse and its mounting on the motor.

Figure 3 is a plan view of the fuse and its mounting detached from themotor.

Figure 4 is an enlarged cross sectional view of the fuse.

Referring now to the drawing in which like characters of referencedesignate similar parts in the various views, III designates a supportfor mounting the fuse upon the cylinder head II, the support preferablybeing formed of strap metal and including a straight flat portion I2,downwardly directed parallel legs I3, and outwardly directed feet I4,which latter are adapted to lie at upon the head of the motor and besecured thereto by bolts I5 passed through suitable openings I6 in thefeet and in the head of the motor.

The fuse comprises a hollow cylindrical body II formed of insulatingmaterial closed at the top by a cap I8 having vents I9 therein. Afusible wire 20 is disposed in the interior of the body and has one endexposed on the exterior of the body as shown at 2 I. The other end ofthe wire is secured to the body by a metal ring 22. A fusible member 23closes the bottom of the body and has the inner face spaced slightlyfrom the fusible wire 20. 'Ihe fusible member 23 is formed of anysuitable material that will burn up at a temperature of about 250degrees F. and melt the fusible wire 20 to open the ignition circuit aswill presently appear.

The body I1 is encased in a cylindrical metal threaded member 24 whichis screwed into a threaded ring 25 carried by an insulating socketmember 26 which is provided with ears 21 that are riveted, as shown at28 to the mounting member Il),

An angular clip 29 is connected to the metal ring 25 and is providedwith a screw 30 to which one terminal 3I of the ignition circuit 32 maybe attached. An angular clip 33 is mounted in the bottom of theinsulating socket member 26 to be engaged by the metal ring 22 to whichthe fusible wire 20 is attached. A set screw 34 forms means forattaching the other terminal 35 of the ignition circuit to the clip 33.The terminal wires 3I and 35 are disposed above the mounting member I0and are trained through respective openings 36 and 31 formed in themounting member so that they will not become accidentally dislodged.

A conventional switch 38 is mounted on the instrument board of theVehicle and controls a circuit formed by Wires 39 and 40 which areconnected to the wires 32 and 35 outside of the mounting member I0. Thepurpose of the switch 3B is to by-pass the ignition circuit around thefuse after the fuse has become burned in an inconvenient place such ason a railroad track, or the like.

In operation the ignition current passes through the wire 3|, clip 29,metal ring 25, metal member 24, fusible wire 20, metal ring 22, clip 33,and wire 35. When a temperature dangerous to the motor is reached, sayabout 250 degrees F. the combustible material 25 will become ignited andwill burn up and consume the fusible wire 20, such combustion beingaccelerated by draft upwardly through the opening 4I in the bottom ofthe socket 26, through the bore of the insulating cylinder I1 andthrough the vent openings I9. Thus the ignition circuit will be brokenuntil a new fuse be screwed in or the switch placed in contact position.

From the above description it is thought that the construction andoperation of the invention will be fully understood without furtherexplanation.

What is claimed is:

An electric fuse comprising a hollow cylindrical insulating body, a capclosing one end of the body and having vent openings, a combustibleelement closing the other end of the body, a fusible circuit wirecarried in the body contiguous to the combustible element and adapted tobe melted by ignition of the combustible element, a metal shell housingthe body and forming one circuit terminal for said fuse, a metal ring onthe body spaced from the shell and forming the other circuit terminalfor the fuse, an insulating socket member housing the shell and thering, and mounting means on the socket member.

ELMER D. STASSEN.

